Self-Forgiveness

Briony is able to atone for her actions, in her mind, by forgiving herself. She says she wanted to give Cecilia and Robbie the happy life they deserved. She convinces herself that by giving them a faux life by means of literature, she has redeemed herself. She was able to bear her mistake, and instead of sulking about it, she did the best thing of which she could think by giving them the happy life they deserved in her novel, albeit a fantasy. It was a grave mistake, and I think she would have found more efficacy by making amends with Cecilia, rather than keeping it all to herself and living in a land as real as Hoth or Tatooine.